This research and research training program emphasizes toxicologic and epidemiologic approaches to the study of the effects of environmental factors on the health of man. Specific examples include the following: metabolism and interactions of pesticides in a variety of animal species, toxic effects of combinations of chemical and physical stresses, experimental pulmonary carcinogenesis, physiology and biochemistry of alveolar macrophages and pulmonary clearance. Epidemiologic studies include study of etiologic factors in chronic non-specific and specific respiratory diseases (occupational, residential and personal smoking exposure), occupational factors in cancer incidence, and evaluation of the risk of childhood cancer from prenatal exposure to radiation. Other studies involve the development of improved methods for measuring respiratory exposure to atmospheric contaminants.